1. Field of the Invention
The present invention relates to a scroll-type pump adapted for use as a compressor for a coolant in, for example, an automobile air-conditioning device.
2. Description of the Prior Art
A so-called scroll-type compressor includes a stationary scroll member and a movable scroll member of the same shape arranged so that they are angularly spaced from each other at an angle of 180.degree.. The movable scroll member rotates about an axis other than its own axis while maintaining contact with the stationary scroll member. Closed chambers formed between the stationary scroll member and the movable scroll member are increased or decreased in volume during the rotation of the movable scroll member. As a result, a fluid medium sucked into the closed chambers is compressed.
In this type of compressor of the prior art, the scroll shape of the scroll members is based on an involute curve based on a circle, a polygon, or a straight line. In this case, the radius of curvature of the scroll member becomes larger as the distance of the scroll member from the center of the scroll increases. The overall shape of a pump having a scroll shape based on the above curves is naturally a substantially circular pillar shape. Thus, if such a pump is housed in a space other than a circular pillar shaped space, such as a trigonally shaped space, it is impossible to effectively use the space.